
KEYS100 Ultramarathon
About This Event
Registration is open for the 19th Annual race across the islands of the Florida Keys--May 15-16, 2027. This chain of unique and inter-connected islands--some inhabited, some not--end in the City of Key West, just 90 miles from Cuba. This is a pavement race, with approximately 75% run on paved bike paths and sidewalks, parallel pedestrian bridges and portions of the old service road. The balance is run on the road shoulder facing traffic--and close to it. (Awareness and caution are paramount when running these sections.) The Florida Keys, known locally as "The Conch Republic", is a spectacular and laid-back sub-tropical paradise, surrounded by the turquoise waters of the Atlantic Ocean and Florida Bay/Gulf of Mexico. The Keys feature great fishing, kayaking, snorkeling and diving, hotels, resorts, B&B's and cuisine and cocktails to fit every budget. There is entertainment to fit every taste, important history and a unique culture, sunsets that will keep you spellbound, special events going on throughout the year including KEYS100, of course, and you don't need a passport to visit here! So, what are you waiting for? We've saved a space for you!
Race Distances
Ready to run?
Registration Pricing
50 Mile Individual Ultra
$305.00
+ $16.25 processing fee
event_busy Goes up to $325.00 after Jan 9, 2027
100 Mile Team Relay
$1050.00
+ $43.00 processing fee
event_busy Goes up to $1110.00 after Jan 9, 2027
50 Kilometer Individual Ultra
$240.00
+ $15.40 processing fee
event_busy Goes up to $270.00 after Jan 9, 2027
50 Mile Team Relay
$540.00
+ $28.00 processing fee
event_busy Goes up to $585.00 after Jan 9, 2027
100 Mile Individual Ultra
$355.00
+ $18.75 processing fee
event_busy Goes up to $395.00 after Jan 9, 2027
Prices from the official registration page, updated several times a day.
Registration links may earn us a small commission at no extra cost to you.
Weather
Frequently Asked Questions
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Race Day Schedule
5/15/2027 05:30
100 Miles Start
5/15/2027 09:00
50 Miles Start
5/15/2027 12:00
50K Start
5/15/2027 05:00
100 Miles Start
5/15/2027 09:00
50 Miles Start
Registration
Registration links may earn us a small commission at no extra cost to you.
Local Running Store
Key West, Florida Keys
Fit2Run Key West is the Southernmost running store in the United States, located on the iconic Duval Street. Serving Key West's vibrant running community and the many runners who come to train and race in the Florida Keys, from the Key West Half Marathon to the Keys 100.
phone (844) 348-2786 language Visit WebsiteRunner's gear
Gear for race day

Honey Stinger Organic Energy Gel
Honey-based gel, caffeine free
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LMNT Zero Sugar Electrolytes, Citrus Salt (30 ct)
1,000 mg sodium per stick, zero sugar
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Body Glide Original Anti-Chafe Balm
Anti-chafe balm for humid long runs
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KEYS100 Ultramarathon
May 15, 2027